Fixing structure of distribution member

ABSTRACT

A fixing structure ( 10 ) of a distribution member has a plurality of pins provided on one of an annular distribution member and a stator in a predetermined arrangement relation in the circumferential direction, and a plurality of holes provided in the other one of the annular distribution member and the stator so that the plurality of pins are fitted thereinto, respectively. In the fixing structure, each pin and a corresponding hole form one fitting set and the tightening margin of each fitting set has a different value.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a structure for fixing adistribution member, and particularly to a fixing structure of anannular distribution member and a stator.

2. Description of the Related Art

In a three phase rotating electric machine having a stator and a rotor,it is normally necessary that a bus bar be provided for each phaseportion of coils, so as to link coils of the same phase together amongdifferent phase portions of coils wound around a stator of the rotatingelectric machine. For example, Japanese Patent Laid-Open Publication2006-180615 (Patent Document 1) discloses a stator of a rotatingelectric machine in which different phase portions of coils are woundaround an annular core and the coils of a same phase are linked by anannular bus bar arranged circumferentially on an annular core. A bus baris provided for each phase and arranged opposite to the face of thecoils disposed on the side of the core. The bus bars of different phasesare arranged in parallel with each other on the side of the core in sucha manner that the bus bars are staggered and zigzag around the annularperiphery of the core. In such a structure, all connection pointsbetween the coils and the bus bars are provided on the circumference ofthe same circle. Each end (or connection terminal) of the coil isconnected to each bus bar using a linkage cylinder which is fitted intoa connecting hole and a cylindrical connector which is fitted into thelinkage cylinder. The linkage cylinder and the connector havelongitudinal slits, and the fitting surfaces thereof are tapered so thatwhen the connector is fitted into the linkage cylinder, the diameter ofthe cylinder increases, while the diameter of the connector decreases.

-   Patent Document 1: Japanese Patent Laid-Open Publication 2006-180615

SUMMARY OF THE INVENTION

With the configuration described Patent Document 1, the bus bars can besecured to the stator. However, if the configuration of the PatentDocument 1 is used without any modification to secure the bus bars tothe stator, accurate positioning of the bus bars relative to the statoris a complex and difficult task, because the plurality of coil ends ofthe coils arranged on the stator must be inserted simultaneously into aplurality of connecting holes formed in the bus bars; if, for example,there are 18 teeth formed on one stator with the coil wound around eachtooth, the position of the coil end relative to the connecting hole mustbe adjusted repeatedly.

An object of the present invention is to provide a fixing structure of adistribution member which facilitates positioning of a bus bar and astator.

A fixing structure of a distribution member according to the presentinvention includes a plurality of pins provided on one of an annulardistribution member and a stator in a predetermined pattern in thecircumferential direction, and a plurality of holes provided in theother one of the annular distribution member and the stator so that theplurality of pins are fitted thereinto. In the fixing structure, eachpin and a corresponding hole form one fitting set and the tighteningmargin of each fitting set has a different value.

In the fixing structure of a distribution member according to thepresent invention, the plurality of pins includes primary reference pinsand secondary reference pins, the secondary reference pins having awider tightening margin with corresponding holes than the tighteningmargin of the primary reference pins with the corresponding holes. It ispreferable that the number of the secondary reference pins is greaterthan the number of the primary reference pins.

In the fixing structure of a distribution member according to thepresent invention, it is preferable that the plurality of holes have thesame diameter, that the tip end of the plurality of pins has a smallerdiameter than the diameter of the plurality of holes, and that theplurality of pins are tapered in a manner that the diameter of the pinsgradually increases from the tip end to the base end thereof, with thediameter of the base end of the pins being larger than the diameter ofthe plurality of holes. It is also preferable that the tip end of thesecondary reference pins has a smaller diameter than the tip end of theprimary reference pins.

In the fixing structure of a distribution member according to thepresent invention, it is preferable that the tapered shape of theplurality of pins is formed using a plurality of ribs provided on eachpin in the circumferential direction.

In the fixing structure of a distribution member according to thepresent invention, it is further preferable that the plurality of pinsare provided on the distribution member and the plurality of holes areprovided on the stator.

In the fixing structure of a distribution member according to thepresent invention, it is also preferable that the primary reference pinsare provided in the vicinity of a connector portion which is provided totake out each phase of coils wound around the stator.

With the above structure including the plurality of pins providedcircumferentially in a predetermined relationship and the plurality ofholes provided to receive each of the plurality of pins, with each pinand the corresponding hole forming one fitting set, the tighteningmargin of each fitting set has a different value, and the fitting sethaving a large tightening margin is used for positioning by press-fit.This facilitates positioning of the stator and the distribution memberwhich serves to allocate bus bars, compared to the case where allfitting sets have the same fitting margin. In other words, thepositioning of the stator and the bus bars can be accomplished much moreeasily.

In the above structure, the number of the secondary reference pinshaving a large tightening margin with the corresponding holes is greaterthan the number of the primary reference pins having a small tighteningmargin with the corresponding holes. Thus, because the fitting sethaving a large tightening margin is used for positioning, the accuracyof positioning can be improved.

Further, in the above structure, the plurality of holes have the samediameter, and the plurality of pins are tapered in a manner that thediameter of the pins gradually increases from the tip end to the baseend thereof, with the diameter of the base end of the pins being largerthan the diameter of the holes. The tip end of the secondary referencepins has a smaller diameter than the tip end of the primary referencepins. Because many secondary reference pins having such a small diameterare provided, the positioning is facilitated during an early stage ofthe insertion process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a fixing structure of a distribution member according to anembodiment of the present invention;

FIG. 2 is a top view of a primary reference fitting portion of FIG. 1;

FIG. 3 is a top view of a secondary reference fitting portion of FIG. 1;

FIG. 4 is a sectional view cut along a line D-D of FIG. 2; and

FIG. 5 is a sectional view cut along a line E-E of FIG. 3.

PARTS LIST

-   10: Fixing Structure-   12: Connector Portion-   14: Bus Bar Supporting Portion-   20: Hole-   30: Primary Reference Fitting Portion-   32: Primary Reference Pin-   34: Primary Reference Slit-   36: Primary Reference Rib-   40, 50: Secondary Reference Fitting Portion-   42: Secondary Reference Pin Portion-   44: Secondary Reference Slit-   46: Secondary Reference Rib

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENT

A preferred embodiment of the present invention will be described belowwith reference to the attached drawings. In the following example, oneprimary reference pin and two secondary reference pins are provided, butthe number of pins is not limited thereto as long as the number ofprimary reference pins is less than the number of the secondaryreference pins.

FIG. 1 shows a fixing structure 10 of a distribution member. A holeprovided in the stator and a corresponding pin provided on the annulardistribution member form a fitting set. In the example shown in FIG. 1,the primary reference fitting portion 30 and secondary reference fittingportions 40, 50 correspond to such a fitting set. FIGS. 2 and 3 are topviews of the primary reference fitting portion 30 and the secondaryfitting portion 40, respectively, of FIG. 1. FIGS. 4 and 5 are sectionalviews along the line D-D of FIG. 2, and the line E-E of FIG. 3,respectively. The fixing structure 10 of the distribution member is usedfor fixing the stator and the annular distribution member. The fixingstructure 10 of the distribution member includes a bus bar supportingportion 14, a connector portion 12, the primary reference fittingportion 30 and the secondary reference fitting portions 40, 50.

The bus bar supporting portion 14 has an annular supporting slit intowhich a plurality of connecting bus bars are inserted in such a mannerthat the bus bars can be insulated from each other. For example, in thethree phase rotating electric machine, the bus bar supporting portion 14has four annular supporting slits corresponding to three phases and theneutral point.

The connector portion 12 is provided for supplying alternating currentto each of U, V, and W phase coils wound around the stator to activatethe three phase rotating electric machine. The connector portion 12 is aconnector which is provided along a portion of the outer periphery ofthe bus bar supporting portion 14 and protrudes outwards.

The primary reference fitting portion 30 includes a primary referencepin 32, a primary reference rib 36, and a hole 20. The primary referencefitting portion 30 is arranged in close proximity to the connectorportion 12.

The primary reference pin 32 is a protrusion provided on the bus barsupporting portion 14, and is tapered in such a manner that the crosssectional area of the pin gradually increases from the tip end to thebase end thereof. As shown in FIG. 2, the primary reference pin 32 has acircular tip end, while the cross section of the primary reference pin32 is in a generally trapezoidal shape when viewed along the line D-D asshown in the sectional view of FIG. 4. The primary reference pin 32 isinserted into the hole 20, described below, from the tip end side tosecure the stator to the bus bar supporting portion 14.

The primary reference ribs 36 are generally triangular trapezoidalportions provided on the bus bar supporting portion 14 and arranged at apredetermined distance from each other by 90° around the primaryreference pin 32 when seen from the above. The cross sectional area ofthe primary reference ribs 36 shown in the top view of FIG. 2 increasesfrom the tip end toward the base end thereof, with the area of the tipend being smaller than the holes 20, and the area of the base end beinglarger than the holes.

The holes 20 are through holes arranged at a predetermined distancesfrom each other by 120° around the stator. The holes 20 have a diameter“r” and are arranged at predetermined positions so as to fit into any ofthe primary reference pins 32, the secondary reference pins 42, andother secondary reference pins of the secondary reference fittingportion 50.

The secondary reference fitting portion 40 includes a secondaryreference pin 42, a secondary reference rib 46, and the hole 20. Thesecondary reference fitting portions 40, 50 are arranged at apredetermined distance from each other by 120° around the bus barsupporting portion 14 relative to the primary reference fitting portion30. Thus, as described above, it is possible to fit the primaryreference pins 32, and the secondary reference pins 42, and thesecondary reference pins of the secondary reference fitting portion 50into the holes 20 arranged at a distance from each other by 120° aroundthe stator. It should be noted that, because the secondary referencefitting portion 40 and the secondary reference fitting portion 50 havethe same configuration, although only the secondary reference fittingportion 40 will be described in the following, this description can beapplied to both components.

Similar to the primary reference pin 32, the secondary reference pin 42is also a protruding portion provided on the bus bar supporting portion14 and tapered in a manner that the cross sectional area of the pingradually increases from the tip end to the base end thereof. As shownin FIG. 3, the secondary reference pin 42 has a circular tip end, whilethe cross section of the secondary reference pin 32 is in a generallytrapezoidal shape when cut along the line E-E as shown in the sectionalview of FIG. 5. The secondary reference pins 42 are inserted into theholes 20 from the tip end side to secure the stator to the bus barsupporting portion 14.

Similar to the primary reference ribs 36, the secondary reference ribs46 are generally triangular trapezoidal portions provided on the bus barsupporting portion 14 and arranged at a predetermined distances fromeach other by 90° around the secondary reference pin 42 when seen fromthe above. The cross sectional area of the secondary reference ribs 46shown in the top view of FIG. 3 gradually increases from the tip endtoward the base end thereof, with the area of the tip end being smallerthan the holes 20 and the area of the base end being larger than theholes.

When the primary reference fitting portion 30 is compared to thesecondary reference fitting portion 40, the diameter of the tip end ofthe primary and secondary reference pin portions 32 and 42 is d1 and d3(d1>d3), as shown in FIGS. 2 and 3. The width of the base end includingthe primary and secondary reference ribs 36 and 46 is d2 and d4 (d4>d2),as also shown in FIGS. 2 and 3. As the diameter of the hole 20 is “r”,as mentioned above, the order of the length of d1, d2, d3, and d4relative to r is d4>d2>r>d1>d3. Therefore, as shown in FIGS. 4 and 5,the relationship of a tightening margin t1 of the primary referencefitting portion 30 relative to a tightening margin t2 of the secondaryreference fitting portion 40 is t2>t1.

Next, the operation of the above structure will be described. During theassembly step of the rotating electric machine, the primary referencepin 32, the secondary reference pin 42, and another secondary referencepin of the secondary reference fitting portion 50 of the bus barsupporting portion 14 formed as the annular distribution member areinserted into the holes 20 formed in the stator. Then, the primaryreference ribs 36, the secondary reference ribs 46, and the secondaryreference ribs of the secondary reference fitting portion 50 areinserted into the holes in a press-fitting manner to secure the bus barsupporting portion 14 to the stator. As described above, because thediameter (r) of the hole 20> the diameter (d1) of the tip end of theprimary reference pin 32> the diameter (d3) of the tip end of thesecondary reference pin 42, the pins can be inserted into the holes in aloose fitting manner during the beginning of the insertion process. Inother words, positioning of the components during the early stages ofinsertion is made easier.

By considering the relationship t2>t1, where t1 is the primary referencetightening margin which is the tightening margin of the primaryreference fitting portion 30 and t2 is the secondary referencetightening margin which is the tightening margin of the secondaryreference fitting portion 40 (note that the tightening margin of thesecondary reference fitting portion 50 is also t2), when the primaryreference ribs 36 and the secondary reference ribs 46 and the secondaryreference rib of the secondary reference fitting portion 50 are insertedinto the holes by press-fit, the secondary reference fitting portions40, 50 having a wider tightening margin can be used for positioning. Inaddition, because the number of the secondary reference fitting portions40, 50 is greater than the number of the primary reference fittingportion 30, the secondary reference fitting portions 40, 50 are dominantand the positioning accuracy of the bus bar supporting portion 14 andthe stator can therefore be improved.

At the end of the insertion process, the bus bar supporting portion 14and the stator can be tightly secured using the secondary referencefitting portions 40, 50 having a wider tightening margin, because thenumber of the secondary reference fitting portions 40, 50 is greaterthan the number of the primary reference fitting portions 30. Thus, bywidening the tightening margin of the secondary reference fittingportions 40, 50 where many pins are provided, floating of the bus barsupporting portion 14 can be alleviated during the assembly of therotating electric machine.

It should be noted that, in the above structure, the primary referenceribs 36 and the secondary reference ribs 46 and the secondary referencerib of the secondary reference fitting portion 50 are used to form thetapered shape of the pins, so that the cross sectional area of the pinscan be decreased compared to the tapered pins formed without using theribs. This contributes to diminish the fitting load of installation.

Also, as the width of the tip end of the secondary reference pin 42 issmaller than the width of the tip end of the primary reference pin 32,that is, d3<d1, and the primary reference fitting portion 30 is arrangedin the vicinity of the connector portion 12, rattling which mayotherwise occur near the connector portion 12 during assembly can beprevented.

What is claimed is:
 1. A fixing structure of a distribution member,comprising: a plurality of pins provided on a bus bar supporting portionof one of an annular distribution member and a stator in a predeterminedarrangement relation in the circumferential direction, the plurality ofpins including a primary reference pin having a cross sectional areawhich gradually increases from a tip end to a base end thereof, and asecondary reference pin having a cross sectional area which graduallyincreases from a tip end to a base end thereof, with the diameter of thetip end of the secondary reference pin being smaller than the diameterof the tip end of the primary reference pin; and a plurality of holesprovided in the other one of the annular distribution member and thestator so that the plurality of pins are fitted thereinto, respectively,wherein a secondary reference tightening margin formed by fitting thesecondary reference pin with a corresponding hole for the secondaryreference pin is wider than a primary reference tightening margin formedby fitting the primary reference pin with a corresponding hole for theprimary reference pin.
 2. A fixing structure of a distribution memberaccording to claim 1, wherein the number of the secondary reference pinsis greater than the number of the primary reference pins.
 3. A fixingstructure of a distribution member according to claim 2, wherein: theplurality of holes have the same diameter, the tip end of the primaryreference pin and the secondary reference pin each have a smallerdiameter than the diameter of the plurality of holes.
 4. A fixingstructure of a distribution member according to claim 3, wherein: thetapered shape of the primary reference pin and the secondary referencepin is formed using a plurality of ribs provided on each pin in acircumferential direction.
 5. A fixing structure of a distributionmember according to claim 1, wherein: the primary reference pin and thesecondary reference pin are provided on the distribution member, and theplurality of holes are provided on the stator.
 6. A fixing structure ofa distribution member according to claim 2, wherein: the primaryreference pin is provided in the vicinity of a connector portion whichprotrudes outward from a portion of an outer periphery of the bus barsupporting portion.